Adding bedroom in basement

[Derek Loda]

I'm looking at a rental property that is currently a 3 bed, 1.5 bath 1300s.f. Single family. Structure is as solid and well maintained house that I've seen. Big negative for the house is that the current owner, a retired gentleman who is a smoker, has therefore made it smell like an ash tray (was painted in the last few years, so no terrible stains) and therefore will get rid of carpet and replace with laminate, and seal and paint throughout. Now what I'm looking at as well is adding a fourth bedroom in the basement. Dry, solid structure, and good ceiling height has made me really look into it. With adding another bedroom, I would also add a shower room in the basement as well so there are two bathing units. I'm looking to hear about thoughts/ experiences/ tips for adding a basement bedroom.